1. Field of the Invention
The present invention relates to a thermoelectric converter for a heat-exchanger, which generates electricity by utilizing a temperature difference between a hot surface and a cold surface of a heat conduction wall of the heat-exchanger, and especially relates to a thermoelectric converter for a heat-exchanger preferably used for generating electricity by utilizing the waste heat from a waste incinerator.
2. Related Art Statement
If a temperature is applied to a connection portion between different kinds of conductors or between different kinds of semiconductors, an electromotive force is generated between a hot side and a cold side. This phenomenon is well known as the Seebeck effect. Moreover, it is well known that heat is directly converted into electric power by using a thermoelectric converting element having such a property.
For example, in Japanese Patent Laid-Open Publication No. 4-86973 (JP-A-4-86973), there is a description such that a thermoelectric power generator module is provided to a wall surface of a combustion chamber made of quartz glass for burning butane gas so as to perform a thermoelectric power generation. The thermoelectric power generator module has a construction such that a plurality of thermoelectric elements are combined to form a thermoelectric element module and insulators are provided to both end surfaces of the thermoelectric element module so as to increase an electromotive force. In the technique described in this publication, a fuel is burnt to perform a thermoelectric power generation. However, since the current rate of efficiency of a thermoelectric conversion is at about 10%, there is a drawback in that the thermoelectric conversion efficiency is low as compared with the other direct thermoelectric conversion systems such as a fuel cell.
Recently, a system has been discussed in which a fuel is burnt not for the thermoelectric power generation, but the thermoelectric power generation is performed to recover an energy from a waste heat. For example, in Japanese Patent Publication No. 58-44842 (JP-B-58-44842), a technique is described in which the thermoelectric power generator module is arranged to an exhaust pipe through which an exhaust gas flows having a high temperature from an engine, so as to perform a recovery of waste heat. In this technique, a suction of the open air is performed by utilizing a venturi effect of the exhaust gas at an outlet of the exhaust pipe and a large temperature difference is maintained. However, in a general incinerator or heating furnace, it is not easy to maintain a large temperature difference mentioned above, and thus it is necessary to use a special cooling device for cooling an exhaust gas to obtain such a large temperature difference. Therefore, there is a drawback that it is difficult economically to perform an energy recovery from a waste heat by using the thermoelectric power generator module.